[webkit-reviews] review granted: [Bug 207827] [JSC] Shrink Structure : [Attachment 391023] Patch

[bugzilla-daemon at webkit.org]

Mark Lam <mark.lam at apple.com> has granted Yusuke Suzuki <ysuzuki at apple.com>'s
request for review:
Bug 207827: [JSC] Shrink Structure
https://bugs.webkit.org/show_bug.cgi?id=207827

Attachment 391023: Patch

https://bugs.webkit.org/attachment.cgi?id=391023&action=review




--- Comment #9 from Mark Lam <mark.lam at apple.com> ---
Comment on attachment 391023
  --> https://bugs.webkit.org/attachment.cgi?id=391023
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=391023&action=review

r=me with other suggestions, and if there's no perf regression.

>> Source/JavaScriptCore/runtime/StructureTransitionTable.h:61
>>  }
> 
> How can this be correct?  FirstInternalAttribute is 1 << 6 i.e. 6 bits. 
There are 11 NonPropertyTransitions i.e. 4 bits.  Total unique bits = 10. 
Aren't we potentially losing the top 2 bits here?

I was wrong.  Yusuke pointed out that we're computing NonPropertyTransition +
1<<6, not NonPropertyTransition << 6.